Daughter of Don Girolamo Flores Zenel de Paredes, a nobleman of Toledo, and Doña Mariana Cranobles de Xaramilo; her birth was accompanied by unusual celestial phenomena. Orphaned very young, she was raised by her older sister and her husband. Mary Ann was a pious child with a devotion to Mary. She was miraculously saved from death several times.

Attracted to religious life at an early age, at ten she made vows of poverty, chastity, and obedience. She initially wanted to be a Dominicannun, but instead became a hermit in home of her sister. Her life changed at that point, and except to attend church, she never left the house again. Given to severe austerities, she slept little, and ate an ounce of dry bread every eight or ten days, surviving solely on the Eucharist which she received during daily Communion. Given to ecstacies; had gifts of prophecy, remote viewing, reading of hearts, healing by making the Sign of the Cross or sprinkling with holy water, and at least once restored a dead person to life.

During a series of earthquakes in 1645, and inevitable epidemics that followed them, in Quito, Ecuador she publicly offered herself as a victim for the city and died shortly after. Immediately after her death there blossomed a pure white lily from her blood. The Republic of Ecuador has declared her a national heroine.